The agency has also failed to maintain proper records for the wells and has not updated its guidelines for dealing with the fracking boom in the oil and gas industry.

EPA’s failings have potentially significant consequences as it oversees more than 700,000 injection wells, of which 172,000 pump 2 billion gallons waste or other materials into the earth each day.

Concerns about fracking have become commonplace all over the country. In places not known for significant seismic activity, like Oklahoma and Ohio, earthquakes have increased near injection well sites. California officials have shut down 11 injection sites because of fears that their waste may be leaking into underground water supplies.

The EPA delegates much of its oversight responsibilities to the states, but has not ensured that the patchwork of agencies around the country adhere to the Safe Drinking Water Act and EPA guidelines, according to the GAO. The report also found that funding for inspections remained constant from 2003 to 2012. Because of inflation, that meant a cut in money available to inspect an ever-increasing number of fracking wells.

The GAO report is not the first investigation to fault EPA for its handling of fracking wells. ProPublica reported two years ago “that the EPA did not know exactly how many wells existed in the United States or what volume of waste was being injected into them, and that it did not possess complete records required to be collected under the Safe Drinking Water Act,” according to reporter Naveena Sadasivam.